Reatividade de IgE específica a Dermatophagoides pteronyssinus (Acari: Pyroglyphidae) e suas frações ligantes de Concanavalina A no soro de pacientes com alergia respiratória

Abstract

House dust mites have been reported as important allergen sources which have been characterized by biochemical assays. Some of these allergens are constituted by glycoconjugates that may show affinity with lectins, such as Concanavalin A (ConA). Material and methods: FNLConA and FLConA components were obtained from Dermatophagoides pteronyssinus crude extract after fractionation on Con A-Sepharose affinity chromatography. Dp crude extract and its fractions were evaluated by ELISA and both Dp and FLConA were evaluated by Immunoblot for IgE in sera of 43 patients with allergy to house dust mites and 41 non-allergic subjects selected by skin prick test. Results: Skin prick test analysis showed that all allergic patients were sensitized to D. pteronyssinus (DP+) and co-sensitized to D. farinae (100%) and Blomia tropicalis (86%). Low molecular weight protein bands was detected in FNLConA, however a broad spectrum of protein bands (14-116 kDa) was visualized in both Dp crude and FLConA extract. ELISA analysis showed absence of difference between IgE reactivity to FNLConA when compared to Dp crude among DP+ patients. On the other hand, a lower IgE reactivity between FLConA and Dp crude was observed. Positive correlations were found when Dp crude was compared to FNLConA and FLConA. Inhibition ELISA showed a partial cross-reactivity between D. pteronyssinus and D. farinae when both Dp crude and FLConA were applied on solid phase. Immunoblot analysis revealed several bands ranging from 14 to 116 kDa in Dp-crude and 22 to 116 kDa in FLConA, although there was heterogeneity among the patients. Conclusions: Concanavalin-A bound components from D. pteronyssinus constitute important glycoconjugate antigens which are involved in mite sensitization.